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ELECTRIC MOTOR. No. 361,274. Patented Am. 19', 1887.

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N PETERi Plmninm n mr. washin im D40 UNITED STATES PATENT OFFIC JAMESXV. EASTON, OF NEW YORK, N. Y.

ELECTRIC MOXTOR.

SPECIFICATION forming part. of Letters Patent No. 361,274, dated April19, 1887.

Application filed July 8, 1886.

To all whom it may concern:

Be it known that I, J AMES W. EAsTor a sub ject of the Queen of GreatBritain, residing in 'New York, in the county and State of New magnetsshall be reduced as much as possible,

. ter of their magnetic attraction.

and that thepoints of magnetic polarization of the armature should be solocated as to be acted upon by the field-magnets to the best pos siblemechanical advantage.

Electro-dynamic motors are now usually constructed with ring-armaturesinmuch the manner of dynamo-electric generators. The fieldmagnets encirclea greater or less portion of the armature and tend to produce magnetismtherein at the points nearly opposite the cen- The'magnetism induced inthe armature by the action of its own coils should be at apoint removedfrom the centers of the field-poles adistance nearly equal to one-fourthof the circumference of the armature. The two forces tend, therefore, toform two different points of magnetic polarization in the armature andcombine to establish a resultant polarization; but to a certain ex tentthey neutralize each other. By removing the greater portion of the ironof the field-mag nets through the central portion of each pole theundesired effect from the poles is to a very great extent removed,'andthe consequent magnetic poles of the armature are moved back to suchpositions that the attraction of the fields upon the armature will beexpended to the best possible advantage to revolve the armature.

Serial No.207.0-15. (to model.)

In the accompanying drawings, Figure 1 is a longitudinal section, andFig. 2 a transverse section,ofa motor embodying the features oftheinvention.

Referring to the drawings, A represents a ring-armature constructed uponthe Gramme principle, and B B the poles of a field-mag net, B, appliedthereto. The central portion of each fieldmagnet is removed, as showmatb and If, leaving two outer portions, 0 c and d d", to eachfield-magnet. By reason of this construction the magnetizing effectwhich the field-magnet has upon the armature is insufficient to causethe consequent poles of the armature to be at the points within or nearthe central line of the attraction of the poles; but they will belocated at or near the points it and 8. Considering the pole-piece B tobe north and the pole-piece B south, it will be evident that theattraction then exerted between the armatures and the field-magnet willbe expended to the best advantage for revolving the armature, as it willbe approximately tangential.

I claim as my invention-- ln an electric motor, the combination of anarmature having polarized and neutral points, field-magnets acting uponthe polarized points, which field-magnets have the central portions oftheir polar projections removed, and are thereby separated a greater orless distance from the neutral points of the armature, substantially asdescribed.

In testimony whereof I have hereunto subscribed my name this th day ofMay, A. D. 1886.

JAMES V. EASTON.

Witnesses:

Tt-ros. TRYoN, CHARLES A. TERRY.

